Signaling for preamble used for random access

ABSTRACT

According to one embodiment, a method of requesting a random access connection between a mobile terminal and a base station includes: receiving, by the mobile terminal, information comprising at least one signature root sequence index, a cyclic shift parameter, and a number of signatures used for representing a boundary between a first signature set and a second signature set; preparing, by the mobile terminal, random access signatures according to the at least one signature root sequence index and the cyclic shift parameter, wherein at least one of the random access signatures is associated with the first signature set and the remaining of the random access signatures are associated with the second signature set; and selecting, by the mobile terminal, a random access preamble from the first signature set or the second signature set based on a message size and a radio condition.

TECHNICAL FIELD

The present invention is directed to different methods for allocatingand choosing dedicated signatures for random access.

BACKGROUND ART

Universal mobile telecommunications system (UMTS) is a 3rd Generation(3G) asynchronous mobile communication system operating in wideband codedivision multiple access (WCDMA) based on European systems, globalsystem for mobile communications (GSM) and general packet radio services(GPRS). The long-term evolution (LTE) of UMTS is under discussion by the3rd generation partnership project (3GPP) that standardized UMTS.

The 3GPP LTE is a technology for enabling high-speed packetcommunications. Many schemes have been proposed for the LTE objectiveincluding those that aim to reduce user and provider costs, improveservice quality, and expand and improve coverage and system capacity.The 3G LTE requires reduced cost per bit, increased serviceavailability, flexible use of a frequency band, a simple structure, anopen interface, and adequate power consumption of a terminal as anupper-level requirement.

FIG. 1 is a block diagram illustrating network structure of an evolveduniversal mobile telecommunication system (E-UMTS). The E-UMTS may bealso referred to as an LTE system. The communication network is widelydeployed to provide a variety of communication services such as voiceand packet data.

As illustrated in FIG. 1, the E-UMTS network includes an evolved UMTSterrestrial radio access network (E-UTRAN) and an Evolved Packet Core(EPC) and one or more user equipment. The E-UTRAN may include one ormore evolved NodeB (eNB) 20, and a plurality of user equipment (UE) 10may be located in one cell. One or more E-UTRAN mobility managemententity (MME)/system architecture evolution (SAE) gateways 30 may bepositioned at the end of the network and connected to an externalnetwork.

As used herein, “downlink” refers to communication from an eNB 20 to aUE 10, and “uplink” refers to communication from the UE to an eNB. TheUE 10 is communication equipment carried by a user and may also bereferred to as a mobile station (MS), a user terminal (UT), a subscriberstation (SS) or a wireless device.

An eNB 20 provides end points of a user plane and a control plane to theUE 10. The MME/SAE gateway 30 provides an end point of a session andmobility management function for a UE 10. The eNB 20 and MME/SAE gateway30 may be connected via an S1 interface.

The eNB 20 is generally a fixed station that communicates with a UE 10and may also be referred to as a base station (BS) or an access point.One eNB 20 may be deployed per cell. An interface for transmitting usertraffic or control traffic may be used between eNBs 20.

The MME provides various functions including distributing pagingmessages to the eNBs 20, security control, idle state mobility control,SAE bearer control, and ciphering and integrity protection of non-accessstratum (NAS) signaling. The SAE gateway host provides assortedfunctions including termination of U-plane packets for paging reasonsand switching the U-plane to support UE 10 mobility.

The MME/SAE gateway 30 will be referred to herein simply as a “gateway”for clarity. However, it is understood that the MME/SAE gateway 30includes both an MME and an SAE gateway.

A plurality of nodes may be connected between the eNB 20 and the gateway30 via the S1 interface. The eNBs 20 may be connected to each other viaan X2 interface and neighboring eNBs may have a meshed network structurethat has the X2 interface.

FIG. 2( a) is a block diagram depicting architecture of a typicalE-UTRAN and a typical gateway 30. As illustrated in FIG. 2( a), the eNB20 may perform functions such as selection for gateway 30, routingtoward the gateway during a Radio Resource Control (RRC) activation,scheduling and transmitting paging messages, scheduling and transmittingBroadcast Channel (BCCH) information, dynamic allocation of resources toUEs 10 in both uplink and downlink, configuration and provisioning eNBmeasurements, radio bearer control, radio admission control (RAC), andconnection mobility control in LTE_ACTIVE state. In the EPC, the gateway30 may perform functions such as paging origination, LTE-IDLE statemanagement, ciphering the user plane, System Architecture Evolution(SAE) bearer control, and ciphering and integrity protection ofNon-Access Stratum (NAS) signaling.

FIGS. 2( b) and 2(c) are block diagrams depicting the user-planeprotocol and the control-plane protocol stack for the E-UMTS. Asillustrated in FIGS. 2( b) and 2(c), the protocol layers may be dividedinto a first layer (L1), a second layer (L2) and a third layer (L3)based upon the three lower layers of an open system interconnection(OSI) standard model that is well-known in the art of communicationsystems.

The physical layer, or first layer (L1), provides an informationtransmission service to an upper layer by using a physical channel. Thephysical layer is connected to a medium access control (MAC) layerlocated at a higher level through a transport channel, with datatransferred between the MAC layer and the physical layer via thetransport channel. Data is transferred via a physical channel betweendifferent physical layers, such as between the physical layer of atransmission side and the physical layer of a reception side.

The MAC layer of Layer 2 (L2) provides services to a radio link control(RLC) layer, which is a higher layer, via a logical channel. The RLClayer of Layer 2 (L2) supports the transmission of data withreliability. It should be noted that although the RLC layer isillustrated in FIGS. 2( b) and 2(c), the RLC layer is not required ifthe MAC layer performs the RLC functions.

The PDCP layer of Layer 2 (L2) performs a header compression functionthat reduces unnecessary control information. This allows efficienttransmission of data utilizing Internet protocol (IP) packets, such asIPv4 or IPv6, over a radio or wireless interface that has a relativelysmall bandwidth.

A radio resource control (RRC) layer located at the lowest portion ofthe third layer (L3) is only defined in the control plane and controlslogical channels, transport channels and the physical channels inrelation to the configuration, reconfiguration, and release of the radiobearers (RBs). A RB signifies a service provided by the second layer(L2) for data transmission between a UE 10 and the E-UTRAN.

As illustrated in FIG. 2( b), the RLC and MAC layers are terminated inan eNB 20 on the network side and may perform functions such asscheduling, Automatic Repeat Request (ARQ), and hybrid automatic repeatrequest (HARQ). The PDCP layer is terminated in an eNB 20 on the networkside and may perform the user plane functions such as headercompression, integrity protection, and ciphering.

As illustrated in FIG. 2( c), the RLC and MAC layers are terminated inan eNB 20 on the network side and perform the same functions as for thecontrol plane. As illustrated in FIG. 2( c), the RRC layer is terminatedin an eNB 20 on the network side and may perform functions such asbroadcasting, paging, RRC connection management, Radio Bearer (RB)control, mobility functions, and UE 10 measurement reporting andcontrolling. As illustrated in FIG. 2( c), the NAS control protocol isterminated in the MME of gateway 30 on the network side and may performfunctions such as a SAE bearer management, authentication, LTE_IDLEmobility handling, paging origination in LTE_IDLE, and security controlfor signaling between the gateway and UE 10.

The NAS control protocol may use three different states. An LTE_DETACHEDstate is used if there is no RRC entity. An LTE_IDLE state is used ifthere is no RRC connection while storing minimal UE 10 information. AnLTE_ACTIVE state is used if the RRC connection is established.Furthermore, the RRC state may be divided into two different states,such as RRC_IDLE and RRC_CONNECTED.

In RRC_IDLE state, the UE 10 may receive broadcasts of systeminformation and paging information while the UE specifies aDiscontinuous Reception (DRX) configured by the NAS and the UE has beenallocated an identification (ID) which uniquely identifies the UE in atracking area. Furthermore, no RRC context is stored in the eNB inRRC-IDLE state.

In RRC_CONNECTED state, the UE 10 has an E-UTRAN RRC connection and acontext in the E-UTRAN, such that transmitting and/or receiving data toand from the eNB is possible. Furthermore, the UE 10 can report channelquality information and feedback information to the eNB.

In RRC_CONNECTED state, the E-UTRAN knows the cell to which the UE 10belongs. Therefore, the network can transmit and/or receive data to andfrom the UE 10, control mobility, such as handover, of the UE, andperform cell measurements for a neighboring cell.

In RRC_IDLE mode, the UE 10 specifies the paging DRX DiscontinuousReception cycle. Specifically, the UE 10 monitors a paging signal at aspecific paging occasion of every UE specific paging DRX cycle.

FIG. 3 illustrates the conventional LTE handover procedure. The UE 10sends a measurement report to the source eNB 20 (S102). The source eNB20 sends a handover request message with the UE 10 context to the targeteNB (S104).

The target eNB 20 sends a handover request response to the source eNB(S106). The handover request response includes the new CRNTI, a portionof a handover command message and information related to random access,such as a dedicated access signature for the UE 10 to make acontention-free random access on the target cell. A signature isreserved at this time.

The source eNB 20 sends the handover command to the UE (S108). Thehandover command includes the new C-RNTI and information related torandom access, such as the dedicated signature for the UE 10 to use.

A random access procedure is performed in the target cell after thehandover command in order for the UE 10 to obtain the timing advance(TA) value. This random access procedure should be contention-free suchthat a signature is reserved to the UE 10 in order to avoid collision.

The UE 10 starts the random access procedure on the target eNB 20 bysending the random access preamble using a dedicated signature (S110).The target eNB 20 sends the random access response message to the UE 10(S112). The random access response message includes the TA and uplinkresource assignment. The UE 10 sends the handover complete message tothe target eNB 20 (S114)

The LTE random access procedure may be either contention-based orcontention-free. The random access preamble is contention-based when theUE 10 randomly chooses the preamble from among the available set ofsignatures. The random access preamble is contention-free when the UE 10is assigned the signature for use by the eNB 20 via dedicated signaling.

DISCLOSURE Technical Problem

The dedicated signature assignment can occur for handover and upon thearrival of downlink data if the UE 10 is not time-aligned. The randomaccess preambles for both contention-based and contention-free randomaccess should be based on Zadoff-Chu sequence with Zero Correlation Zone(ZC-ZCZ). The current LTE random access procedure uses two sets ofsignatures.

Technical Solution

In one aspect of the present invention, a method of requesting a randomaccess connection between a wireless mobile terminal and a base stationis provided. The method includes receiving information including atleast one signature root sequence index, a cyclic shift parameter and asignature set identifier representing a boundary between a firstsignature set corresponding to a first transport format and a secondsignature set corresponding to a second transport format and preparingrandom access signatures according to the at least one signature rootsequence index and the cyclic shift parameter, wherein at least one ofthe random access signatures is associated with the first signature setand the rest of the random access signatures are associated with thesecond signature set.

It is contemplated that the signature set identifier comprises aplurality of steps, each of the plurality of steps including a pluralityof signatures. It is further contemplated that the signature setidentifier comprises one of a plurality of predefined borders betweenthe first signature set and second signature set.

In another aspect of the present invention, a mobile terminal forrequesting a random access connection with a base station is provided.The mobile terminal includes a transmitting unit for transmittinginformation, a receiving unit for receiving information, a display unitfor displaying information, an input unit for receiving inputs from auser and a processing unit processing received information including atleast one signature root sequence index, a cyclic shift parameter and asignature set identifier representing a boundary between a firstsignature set corresponding to a first transport format and a secondsignature set corresponding to a second transport format, and preparingrandom access signatures according to the at least one signature rootsequence index and the cyclic shift parameter, wherein at least one ofthe random access signatures is associated with the first signature setand the rest of the random access signatures are associated with thesecond signature set.

It is contemplated that the signature set identifier comprises aplurality of steps, each of the plurality of steps including a pluralityof signatures. It is further contemplated that the signature setidentifier comprises one of a plurality of predefined borders betweenthe first signature set and second signature set.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. It is to beunderstood that both the foregoing general description and the followingdetailed description of the present invention are exemplary andexplanatory and are intended to provide further explanation of theinvention as claimed.

These and other embodiments will also become readily apparent to thoseskilled in the art from the following detailed description of theembodiments having reference to the attached figures, the invention notbeing limited to any particular embodiments disclosed.

Advantageous Effects

An advantage of the first scheme is that a large number of preambles maybe generated that are completely independent from the preambles used forcontention-based random access. Advantages of the second scheme are thatno additional ZC indexes are necessary and there is no need to use a newroot sequence. An advantage of the third scheme is that no additional ZCindexes are required. An inconvenience of the fourth scheme is adecreased number of available preambles for non-contention based RACH,thereby increasing the collision probability.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention. Features, elements, and aspects of the invention that arereferenced by the same numerals in different figures represent the same,equivalent, or similar features, elements, or aspects in accordance withone or more embodiments.

FIG. 1 illustrates the network structure of an E-UMTS.

FIG. 2( a) illustrates the architecture of an E-UTRAN and gateway.

FIGS. 2( b) and 2(c) illustrate the user-plane protocol andcontrol-plane protocol for the E-UMTS.

FIG. 3 illustrates the conventional handover procedure for LTE.

FIGS. 4( a) and 4(b) illustrate a method of dedicated signatureallocation according to one embodiment of the present invention.

FIG. 5 illustrates a block diagram of a mobile station according to thepresent invention.

BEST MODE

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The present invention presents several schemes for allocatingdedicated signatures.

In a first scheme, signatures are allocated from separate rootsequences. In this scheme, the signatures used for non-contention basedrandom access are generated using different ZC root sequences than thoseused to generate contention-based random access preambles.

An advantage of the first scheme is that a large number of preambles maybe generated that are completely independent from the preambles used forcontention-based random access. Disadvantages of the first scheme arethat the use of a new root sequence in a cell results in moreinterferences, more root sequences used per cell and cross-correlationand detection are more complex.

Ina second scheme, signatures are allocated from the unused space of therandom signature root index. In this scheme, different code resourcesare used for dedicated and random signatures.

The last sequence index used for contention-based signature opportunityis not necessarily fully allocated to generate the 64 signatures sincethe cyclic shift value is related to the cell size in that the shiftmust be larger than the maximum propagation delay for a given cell size.This allows the allocation of the remaining unused signatures to thecontention-free access procedure.

Advantages of the second scheme are that no additional ZC indexes arenecessary and there is no need to use a new root sequence. Adisadvantage of the second scheme is that the number of remainingsignatures opportunity is not fixed and may also be zero depending onthe cell size or, in other words, on the length of the cyclic shift.

In a third scheme, signatures are allocated from the same root indexusing different time/frequency resources. The same code resources areused for dedicated and random signatures. In this scheme,contention-based and contention-free RACH signature opportunities areallocated from the same cyclic shifted versions over the same ZCsequences index.

An advantage of the third scheme is that no additional ZC indexes arerequired or, in other words, there is no need to use a new rootsequence. A disadvantage of the third scheme is that the distinctionbetween contention-free and contention-based preambles is made by thetime/frequency resources used for RACH since there is no codedistinction between contention-free and contention-based preambles,thereby requiring additional signaling.

In a fourth scheme, signatures are allocated from the same root indexusing the same time/frequency resources. This scheme consists ofallowing the reservation of some preambles from the set of preamblesused for the contention-based random access procedure in a semi-staticway. For example, 16 preambles could be reserved. An inconvenience ofthe fourth scheme is a decreased number of available preambles fornon-contention based RACH, thereby increasing the collision probability.

A preferred scheme is a hybrid between the second and fourth schemes.This hybrid scheme considers the advantages and disadvantages of thefour schemes in order to minimize interferences introduced by the use ofnew root sequences and signaling.

The hybrid scheme allocates the dedicated signatures from the unusedspace of the random signature root index when there is unused space. Thefourth scheme is utilized if more dedicated signatures are needed andsome preambles are reserved from the contention-based random accesspreambles. The number of signatures that may be reserved among thecontention-based signature sets is predetermined.

FIG. 4 illustrates dedicated signature allocation according to thepresent invention. In FIG. 4, it is assumed that the UE 10 knows theroot sequences and cyclic shift value used in the cell where it will usethe dedicated signature and that the hybrid method is used for theallocation of dedicated signatures.

One way to indicate to the UE 10 which signature has been reserved forits use is to simply indicate a number out of the total number ofavailable signatures such that the UE knows how many cyclic shifts itwill have to apply in order to generate the signature. The total numberof available signatures is the number of signatures that can begenerated from all the root sequences used in a given cell. The UE 10will implicitly know that it must apply the cyclic shifts to rootsequence #B if the number of cyclic shifts is higher than the max numberof cyclic shifts applicable on root sequence #A.

However, this method requires that the eNB 20 send at least 6 bits ofinformation to the UE 10. There are several options for optimizing themethod. For all the options, the number of signatures that are reservedmust be indicated to the UEs 10 that perform contention-based access,such as by being broadcast on the BCCH.

A first option for allocating dedicated signatures is to reduce thenumber of information bits to less than 6 bits is by defining in thestandard that the signature for the contention-based random access forwhich reservation is allowed are the last signatures generated from theroot sequence and to start numbering from the end, as illustrated by thearrow in FIG. 4( a).

The first option is dependent on the number of signatures that can bereserved, such as only 4 bits being necessary if the number ofsignatures that can be reserved is fixed at 16. For example, the eNB 20may reserve signature 64 and send the information “3” to the UE 10. Asillustrated in FIG. 4( a), 3 unused signatures are available. The firstoption requires that the space on the ZC index for reserved signaturesbe contiguous and located at the end of the index before the unusedspace.

One disadvantage of the first option is that all the signatures that canbe reserved are from the same set and, therefore, the UE cannot choose aset, such as to indicate the required resources/channel quality. Thefirst option also reduces the number of signatures available forcontention-based only in one set and increases the collision probabilityfor only one category of users.

A second option for allocating dedicated signatures addresses thedisadvantages of the first option. The second option allocates thededicated signatures between the two sets of signatures proportionallyto the size of the set instead of allocating the reserved signatures atthe end of the index from among the 64 signatures used for thecontention-based random access.

For example, if Nr signatures can be reserved among the 64contention-based random access signatures, those signatures are reservedbetween the two sets such that one part will be at the end of the firstset and the other part at the beginning of the second set. The number ofsignatures reserved in each of the two sets can be calculated accordingto the following equation:

NRset1=ceil(Nset1/64*(Nr−Nunused)) and NRset2=Nr−NRset1−Nunused

-   -   Where:        -   Nset1 the number of signatures in set 1        -   Nset2 the number of signatures in set 2        -   Nunused is the number of signatures that are not used in the            root sequences        -   NRset1 the number of reserved signatures in set 1        -   NRset2 the number of reserved signatures in set 2        -   Ceil indicates integer (upper integer)

There are two alternatives to indicate to the UE 10 which signature touse for the second option. The first alternative is the less optimizedalternative and indicates the signature with a number from 6 to 8 bits,with the upper bound predetermined depending on the number of signaturesavailable in the unused space of the ZC index.

The second alternative, which is illustrated in FIG. 4( b), consists ofsending offset information to indicate the signature to use, with thenumber of bits of the offset information dependent on the number ofsignatures that can be reserved. For example, 4 bits would be requiredif 16 signatures are dedicated without any unused space. The countingwould be done from the first reservable signature of set 1 in FIG. 4( b)toward the last reservable signature of set 2 or from the end of theindex toward the beginning of the sequence if the signature comes fromthe unused space of an index.

The UE 10 must choose between signatures in two groups in the secondoption for allocating dedicated signatures, as illustrated In FIG. 4(b). In order to optimize the resource allocation for the transmission ofdata in message 3 illustrated in FIG. 3, the UE 10 can be assigned asignature according to the required resources, such that the eNB 20indicates to the UE the transport format to be used in message 3together with the dedicated signature.

An advantage of this option for choosing a dedicated signature is thatthe eNB 20 designates only one signature. A disadvantage of this optionis that the size of message 3 illustrated in FIG. 3 must accommodate theassigned signature.

An alternative option for choosing the dedicated signature is that theeNB 20 reserves two signatures each time, one from each signature set,such that the UE 10 chooses the signature according to the amount ofdata it must transmit. The eNB 20 should indicate for which transportformats of message 3 illustrated in FIG. 3 and/or radio conditions theUE 10 could use each reserved dedicated signature. The disadvantage ofthis option is that two signatures must be reserved.

FIG. 5 illustrates a block diagram of a mobile station (MS) or UE 10.The UE 10 includes a processor (or digital signal processor) 510, RFmodule 535, power management module 505, antenna 540, battery 555,display 515, keypad 520, memory 530, SIM card 525 (which may beoptional), speaker 545 and microphone 550.

A user enters instructional information, such as a telephone number, forexample, by pushing the buttons of a keypad 520 or by voice activationusing the microphone 550. The microprocessor 510 receives and processesthe instructional information to perform the appropriate function, suchas to dial the telephone number. Operational data may be retrieved fromthe Subscriber Identity Module (SIM) card 525 or the memory module 530to perform the function. Furthermore, the processor 510 may display theinstructional and operational information on the display 515 for theuser's reference and convenience.

The processor 510 issues instructional information to the RF module 535,to initiate communication, for example, transmits radio signalscomprising voice communication data. The RF module 535 comprises areceiver and a transmitter to receive and transmit radio signals. Anantenna 540 facilitates the transmission and reception of radio signals.Upon receiving radio signals, the RF module 535 may forward and convertthe signals to baseband frequency for processing by the processor 510.The processed signals would be transformed into audible or readableinformation outputted via the speaker 545, for example. The processor510 also includes the protocols and functions necessary to perform thevarious processes described herein.

Depending on implementation, it is possible that the present inventioncan take the form of an entirely hardware embodiment, an entirelysoftware embodiment or an embodiment containing both hardware andsoftware elements. A software embodiment may include, but not be limitedto, to firmware, resident software, microcode, etc.

Furthermore, the invention can take the form of a computer programproduct accessible from a computer-usable or computer-readable mediumproviding program code for use by or in connection with a computer orany instruction execution system. For the purposes of this description,a computer-usable or computer readable medium can be any apparatus thatcan contain, store, communicate, propagate, or transport the program foruse by or in connection with the instruction execution system,apparatus, or device.

A data processing system suitable for storing and/or executing programcode will include at least one processor coupled directly or indirectlyto memory elements through a system bus. The memory elements can includelocal memory employed during actual execution of the program code, bulkstorage, and cache memories which provide temporary storage of at leastsome program code in order to reduce the number of times code must beretrieved from bulk storage during execution.

Other components may be coupled to the system. Input/output or I/Odevices (including but not limited to keyboards, displays, pointingdevices, etc.) can be coupled to the system either directly or throughintervening I/O controllers. Network adapters (e.g., modem, cable modem,Ethernet cards) may also be coupled to the system to enable the dataprocessing system to become coupled to other data processing systems orremote printers or storage devices through intervening private or publicnetworks.

It should be understood that the logic code, programs, modules,processes, methods, and the order in which the respective elements ofeach method are performed are purely exemplary. Depending on theimplementation, they may be performed in any order or in parallel,unless indicated otherwise in the present disclosure. Further, the logiccode is not related, or limited to any particular programming language,and may be comprise one or more modules that execute on one or moreprocessors in a distributed, non-distributed, or multiprocessingenvironment.

The method as described above may be used in the fabrication ofintegrated circuit chips. The resulting integrated circuit chips can bedistributed by the fabricator in raw wafer form (that is, as a singlewafer that has multiple unpackaged chips), as a bare die, or in apackaged form. In the latter case, the chip is mounted in a single chippackage (such as a plastic carrier, with leads that are affixed to amotherboard or other higher level carrier) or in a multi-chip package(such as a ceramic carrier that has either or both surfaceinterconnections of buried interconnections).

In any case, the chip is then integrated with other chips, discretecircuit elements, and/or other signal processing devices as part ofeither (a) an intermediate product, such as a motherboard, or (b) andend product. The end product can be any product that includes integratedcircuit chips, ranging from toys and other low-end applications toadvanced computer products having a display, a keyboard or other inputdevice, and a central processor.

Therefore, it should be understood that the invention can be practicedwith modification and alteration within the spirit and scope of theappended claims. The description is not intended to be exhaustive or tolimit the invention to the precise form disclosed. These and variousother adaptations and combinations of the embodiments disclosed arewithin the scope of the invention and are further defined by the claimsand their full scope of equivalents.

As the present invention may be embodied in several forms withoutdeparting from the spirit or essential characteristics thereof, itshould also be understood that the above-described embodiments are notlimited by any of the details of the foregoing description, unlessotherwise specified, but rather should be construed broadly within itsspirit and scope as defined in the appended claims. Therefore, allchanges and modifications that fall within the metes and bounds of theclaims, or equivalence of such metes and bounds are intended to beembraced by the appended claims.

The foregoing embodiments and advantages are merely exemplary and arenot to be construed as limiting the present invention. The presentteaching can be readily applied to other types of apparatuses.

The description of the present invention is intended to be illustrative,and not to limit the scope of the claims. Many alternatives,modifications, and variations will be apparent to those skilled in theart. In the claims, means-plus-function clauses are intended to coverthe structure described herein as performing the recited function andnot only structural equivalents but also equivalent structures.

INDUSTRIAL APPLICABILITY

The present invention is directed to different methods for allocatingand choosing dedicated signatures for random access.

1-6. (canceled)
 7. A method of requesting a random access connectionbetween a mobile terminal and a base station, the method comprising:receiving, by the mobile terminal, information comprising at least onesignature root sequence index, a cyclic shift parameter, and a number ofsignatures used for representing a boundary between a first signatureset and a second signature set; preparing, by the mobile terminal,random access signatures according to the at least one signature rootsequence index and the cyclic shift parameter, wherein at least one ofthe random access signatures is associated with the first signature setand the remaining of the random access signatures are associated withthe second signature set; and selecting, by the mobile terminal, arandom access preamble from the first signature set or the secondsignature set based on a message size and a radio condition.
 8. A mobileterminal for requesting a random access connection with a base station,the mobile terminal comprising: a transmitting unit for transmittinginformation; a receiving unit for receiving information; a display unitfor displaying information; an input unit for receiving inputs from auser; and a processing unit configured to: process informationcomprising at least one signature root sequence index, a cyclic shiftparameter, and a number of signatures used for representing a boundarybetween a first signature set and a second signature set; prepare randomaccess signatures according to the at least one signature root sequenceindex and the cyclic shift parameter, wherein at least one of the randomaccess signatures is associated with the first signature set and theremaining of the random access signatures are associated with the secondsignature set; and select a random access preamble from the firstsignature set or the second signature set based on a message size and aradio condition.